läbimõõtude suhe, β
square root of the ratio of the area of the throat of the primary device to the internal area of the measuring pipe upstream of the primary device, ruutjuur mõõtevahendi/arvesti kurgu pindala ja mõõtetoru sisepindala suhtest mõõtevahendist ülesvoolu, ratio of the diameter of the orifice of the primary device to the diameter of the conduit upstream of the primary device
